ML090850560
| ML090850560 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/30/2008 |
| From: | Tallman D Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| Shared Package | |
| ML090830613 | List:
|
| References | |
| DPG 09-097 | |
| Download: ML090850560 (21) | |
Text
Rancho Seco Final Status Survey Summary Report October 29, 2008 Industrial Area Railway Survey Unit F8340011 Prepared By: Dan A. Tallman__ Date: October 30, 2008 FSS Engineer Reviewed By:: 'q *ate: at II I¶* Ito2 Lead FSS Engineer Approved By: ?2 Date: - o Dismantlement Superintendent, Radiological
FINAL STATUS SURVEY
SUMMARY
REPORT Survey Unit:
F834001 1, Industrial Area Railway Survey Unit
Description:
The rail system was used to transport radioactive material from the site to the out of state waste disposal facilities. Even though the packages met DOT requirements for shipment, there is the potential for a small amount of contamination to be deposited along the rail right of way. There were no reports of rail contamination in the HSA however, during characterization surveys; documented evidence of contamination along the rail spur near the Turbine building was discovered. A gas proportional detector was used to survey the asphalt surroundinq the rail spur within the IA. The mean value for paved surfaces was 3,653 dpm/100 cm with one isolated area discovered by scan to be contaminated to 43 pCi/g Cs-137. This contaminated area (-' 3 by 4 meters) was located approximately 15 meters west of the north turbine laydown area (826025). A 10 by 10 meter boundary has been established surrounding this area of discovery and serves as the boundary for 8340011. Based on the classification procedure (DSIP-0020) and levels of activity reported, the area was determined to be a Class 1 survey unit.
Survey Unit Design Information:
The Survey Unit Design Parameters are presented in Table 1 below. The survey unit and measurement locations are depicted on the maps in Attachment 1. Direct measurement locations were determined using a random-start, fixed grid pattern and 100 m2 were scanned for 100% coverage. Direct Gamma measurements were collected at each direct measurement location and analyzed by the Genie 2000 Gamma Analyst. The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.
Page 2 of 7 FSS Summary Report F8340011
Table 1. Survey Unit Design Parameters Survey Design Parameter Value Comment Survey Area: F834 Industrial Area Railway Survey Unit: 0011 Open Land Area - PAVED Class: 1 LTP Table 5-4 SU Area (m2): 100 Evaluator: D.A.Tallman DCGL Cs137 surrogate (pCi/g): 51.2 Area Factor: 3 Class 1 Design DCGLemc (pCi/g): 154 Class 1 LBGR (pCi/g): 25.6 Default = 50% DCGL Design Sigma (pci/g): 10.2 DTBD-06-001, Table 5-4D Type I Error: 0.05 Type II Error: 0.05 Nuclide: Cs137 Sample Area (m2): 6.6 Class 1 Total Area Scanned (M2 ): 100 Scan Coverage (%): 100% Class 1 Zl1 ,, : 1.645 ZI-0 : 1.645 Sign P: 0.99379 Calculated Relative Shift: 2.5 Relative Shift Used: 2.5 Uses 3.0 if Rel Shift >3 N-Value: 12 Design N-Value + 20%: 15 NUREG-1575 Table 5-5 Grid Spacing L: 2.6 Class 1 Page 3 of 7 FSS Summary Report F8340011
Survey Results:
A total of 16 direct measurements were made in F83400 11. The results including mean, median, standard deviation and range are shown in Table 2. All of the direct measurements were less than the DCGL. Two (07 & 08) of the Discrete Particle (DP) scan measurements indicated areas of elevated activity. Observed activity from the DP scans ranged from 6819 - 9323 cpm, while the activity observed from the ISOCS scan measurements were reported at < 0.24 pCi/g Co60 (MDA) and < 0.204 pCi/g Cs137.
Gamma Direct measurements were counted to the MDC shown in Table 2-1 of .
Table 2. Direct Measurement Results (all activity values in pCi/g)
Measurement ID Cs137 MDA Cs137 Activity Uncertainty Mean: 9.68E-01 Median: 9.73E-01 Standard Deviation: 3.30E-02 Range: 8.93E-01 to 1.02E00 F8340011 A0001GD 9.22E-01 < 9.22E-01 F8340011 A0002GD 9.31E-0l < 9.31E-01 F8340011 A0003GD 1.02E00 < 1.02E00 F8340011 A0004GD 9.98E-01 < 9.98E-01 F8340011 A0005GD 9.56E-01 < 9.56E-01 F8340011 A0006GD 9.65E-01 < 9.65E-01 F8340011 A0007GD 8.93E-01 < 8.93E-01 F8340011 A0008GD 9.74E-01 < 9.74E-01 F8340011 A0009GD 9.92E-01 < 9.92E-01 F8340011 A0010GD 1.01E00 < 1.01E00 F8340011 A00l1GD 9.91E-01 < 9.91E-01 F8340011 A0012GD 9.77E-01 < 9.77E-01 F8340011 A0013GD 9.78E-01 < 9.78E-01 F8340011 A0014GD 9.49E-01 < 9.49E-01 F8340011 A0015GD 9.72E-01 < 9.72E-01 F8340011 A0016GD 9.67E-01 < 9.67E-01 Page 4 of 7 FSS Summary Report F8340011
Survey Unit Data Assessment:
The survey design required 16 direct measurements for the Sign Test. The critical value and the results of the Sign Test are presented in Table 3. The sample mean and median values were less than the DCGL. The sample standard deviation was less than the design standard deviation so no additional samples were required.
Page 5 of 7 FSS Summary Report F8340011
Table 3. Data Assessment Results Survey Results Parameter Value Comment Actual Direct Measurements (N): 16 Median (pci/g): 9.73E-01 Mean (pCi/g): 9.68E-01 Standard Deviation (pci/g): 3.30E-02 Maximum (pCi/g): 1.02E00 Sign Test Final N Value: 16 S+ Value: 16 Critical Value: 11 Sufficient Samples Collected: Yes Maximum Value < DCGL: Yes Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: Yes Class 1 Standard Deviation <= Sigma: Yes Pass the Sign Test? Yes Reject the Null Hypothesis? Yes The survey unit passes all conditions? Yes Page 6 of 7 FSS Summary Report F8340011
Survey Unit Investigations and Results:
Two investigations (DP scan grids 07 & 08) were required for the scan measurements and the results are reported in Attachment 3. The EMC unity rule was not exceeded as shown in Table 3-1.
ALARA Statement:
As stated in Chapter 4 of the LTP, as long as the residual activity within the survey unit is less than the DCGL (i.e. the survey unit average activity is less than the DCGL and the EMC criterion has been met), the ALARA criterion has been met.
Changes in Initial Survey Unit Assumptions:
The survey unit was designed as a Class 1 land survey and the sample results are consistent with that classification. The variability of the survey results was less than the characterization data used for survey design. Two potential areas of elevated activity were detected and evaluated as shown in Attachment 3. Therefore the EMC criterion was met.
==
Conclusion:==
The FSS of this survey unit was properly designed as a Class 1 survey based on Table 5-4 of the LTP. The required number of direct measurements was made and the scan coverage met the requirement of Table 5-6 of the LTP. All of the direct measurements were less than the DCGL. Two investigations were required.
The direct measurement data support rejection of the null hypothesis, providing high confidence that the survey unit satisfied the release criteria and that the data quality objectives were met.
It is concluded that survey unit F8340011 meets the release criteria of 10CFR20.1402.
Page 7 of 7 FSS Summary Report F8340011
Attachment 1 Maps October 29, 2008 Survey Unit F8340011
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Approximate surface area- 100 m2 Turbine Building 00 Uj INDUSTRIAL AREA RAILWAY 4:o GENERAL ARRANGEMENT PLAN VIEW SURFACE AREA ESTIMATE SACRAMENTO MUNICIPAL UTILITY' DISTRICT F8340011-Mi SHEET 1 of i 4-r))
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- SMUDSACRAMENTO MUNICIPAL LOCATIONS DETAIL UTILITY DISTRICT F8340011-M2 SHEET 2 of 2
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Attachment 2 Instrumentation October 29, 2008 Survey Unit F8340011
Table 2-1. Survey Unit Instrumentation Detector Detector Serial Instrument Model No MDC No.
Inspector N/A 08051294 Asphalt- 1.02 pCi/g Cs-137 Asphalt - 0.95 pCi/g Co-60 ISOCS N/A 1983920 Asphalt - 0.399 pCi/g Cs-137 Asphalt - 0.240 pCi/g Co-60 M2350 44-10 190666 Asphalt - 6.4 pCi/g Cs- 137 (su1) 180738 I
"DTBD 05-012 Eberline SPA-3 and Ludlum 44-10 Detector Sensitivity (MDC)."
Table 2-2. Investigation Criteria and DCGL Instrument Parameter Value ISOCS Investigation Criteria - Scan 2 Asphalt- 20 pCi/g Cs-137 Asphalt - 5 pCi/g Co-60 InSpector Investigation Criteria - Direct 3 Asphalt - 154 pCi/g Cs-137 Asphalt - Detectable Co-60 M2350/44-10 Investigation Criteria - Scan 4 8785 cpm 4 All DCGLw 51.2 Cs-137 12.6 Co-60 All DCGLEMc 154.28 pCi/g Cs-137(surr.)
2 "DTBD 06-003, Use of In situ Gamma Spec for FSS" rounded down for conservatism for Cs137/Co60 respectively LTP Chapter 5, Table 5-7 (positive Co60 measurements will be investigated).
4 DSIP-0510 encl 8.6 - and "Discrete Particle Detection Using the Ludlum 2350-1 and 5.08 by 5.08 NaI Detectors RFD 3/27/07".
Page 2 of 2 Att. 2 Instrumentation F8340011
Attachment 3 Investigation October 29, 2008 Survey Unit F8340011
Table 3-1 Survey Unit Investigation Investigation Initial Value Investigation Elevated Area DInvestigation nvtao Res Aea(mUnity DCGLemc Rvesuigti Eeate) Factor Result (pCi/g) Fraction Level (cpm) (cpm) (pCi/g)
(DP) 07GS 8785 9312 < MDA 1 NA NA NA <DCGLw NA (DP) 08GS 8785 9323 < MDA 2 NA NA NA <DCGLw NA DCGL = SU Mean = 0.019 Survey Unit Remainder 51.2 0.968 Co60 - 1.04 pCi/g I Cs137 - 1.10 pCi/g (InSpector 1000 w/2x2 Nal detector) 2 Co60-O.995pCi/g/Cs137 -1.1OpCi/g (InSpector 1000w/2x2Naldetector)
DP Scan grids 07&08 exceeded IL of 8785 cprn. Investigation using the InSpector 1000 resulted in the Investigation activity results recordedabove.
EMC Unity Sum NA Page 2 of 2 Att. 3 Investigation F8340011
Attachment 4 Data Assessment October 29, 2008 Survey Unit F8340011
F8340011 Quantile Plot Cs137 DCGL = 51.2 pCi/g 1.040 t 1.020
~j~
1.000 -
0.980 I 0 0.973 0.960
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0.940'-1 0.920 0.900 It~ 0.8800 0 20 40 60 80 100 Percentile j* *Activity - Median -- - 75th Percentile -- - - 50th Percentile 00
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F8340011 Scatter Plot Cs137 DCGL = 51.2 pClIg 1.20E+00 1.007 1.00E=+00 - 0 = 0,, 0 .2-- 1 -A Q .,-r-. .e.o 0.908
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0.00E+00 i Measurement Locations o Activity - Average - - "+3StDev" - - -- 3StDev" I r1 00 A
0 F8340011 Frequency Plot Cs1 37 DCGL = 51.2 pCi/g 7
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0 N Z(N N N Q) 4;- R, Ný Bins - Upper End Value (pCi/g) 00 CA